Process of treating organic substances in presence of vanadium compounds.



mar, III, 702,)

UNITED STATES PATENT OFFICE.

ERICH OPPERMANN, OF HOOHST-ON-THE-MAIN,-GERMANY, ASSIGNOR TO FARBWERKE, VORM. MEISTER, LUCIUS & BRI TNING, OF HOOHST- ON-THE-MAIN, GERMANY, A

CORPORATION OF GERMANY.

PROCESS OF TREATING ORGANIC S UOSTANCES IN PRESENCE OF VANADIUM COMPOUNDS.

- Specification of Letters Patent.

I Patented June 12, 1906.

Application filed August 31, 1904. Serial 'No. 222,837

To all whom, it may concern: -Be it known that I, Enron OPPERMANN, Ph. D., chemist, a citizen of the Empire of Germany, residing at Hochst-on-the-Main, Germany, have invented certain new and useful Improvements in the Process of ,Treating Organic Substances by.Electrol sis in Presence of Vanadium Compounds, which the following is a specification.

It is known that the higher oxids of vanadium are excellent oxidizing agents, (Damhas hitherto been made of this propertyas,

. for instance, in the manufacture of fuchsin regeneration according to teursc'ient'lfique, 1879) 'in color-printing and the manufacture of anilin-black. In all cases, however, vanadium serves as a catalytic agent of oxygen.

The easy oxidabilityof the lower oxids of vanadium has also been studied; but this energetic reducing power has hardly been used hitherto. cation of so excellent an oxidizing or reducing agent are partly to be found in the comparatively high price of vanadium salts and partly in the inconvenience and expense of when merely chemically emloyed. It would have been impossible uner these circumstances to use a substance almost unequalled in its various applications.

I This inconvenience is avoided by the present both at the anode process.

v I have found that vanadium compounds in an electrolyt1c bath are excellent depolarizers and cathode. The rapidity of carrylng oxygen and hydrogen to the sis.

mstantaneous acceptors bemlg ve great,, (indigo is reduced yan one part of vanadium salt oxidizes one thousand parts of anilin to anilinblackinpresence ofoxidizinga ents,) only small quantities of'van'adium salts. need be used for reducing or oxidizing by electroly- By this favorable combination (not 'to be foreseen) of the hitherto unused advantages of vanadium as oxidizing or reducing agent and the application of electrolytic oxygen and hydrogen I, found an excellent process for oxidizing and reducing inorganic and organic substances in an electrolytic bath.

No' special (organic) solvents need be employed neither is a diaphragm re uisite, as in the process of German Patent 0. 117,129,

yet only little practical use Schmid Baldenspenger (M Ont-- The reasons for this limited applidated April10,1899. Compared with other activating agentssuch, for instance, as chromates and manganates-the various oxess, for to every degree of oxidation of v a1 1adium belongs a certain reducing or oxidizing potential-that is to say, the various oxids of vanadium produced in the electrolytic bath have a oxidizing power on inorganic or organic substances Introduced into the solution. it is apparent from Example III that azobenzene is reduced to benzidm by means of electrolytic h drogen in presence of V 0 ,On the other and-indigo is reduced b the highest reducing potential of V 0 he higher oxidized vanadiumcompounds (V 0 orV O may be used for oxidizing purposes, yet the reduction of sulfuric acid to SO by'means of V 0 in a hot concentrated sulfate solution s also an example of the reducing power of this cellent oxidizing power of the highest vanapractical application of this property has already been made in 128,616, dated March 22, 1900, relating to the process of manufacturing sulfuric anhydrid by de Haen.

Ewample ].0:c'idat'i'on of anthracenc. Into a vessel lined with lead ,sei'ving as anode, is introduced sulfuric acid of twenty-per-cent. stren th as electrolyte with a quantity of vana ic acid dissolved thereinfor instance, one per cent. Lead, for instance, maybe used as cathode. The anthracene to be oxidized is introduced into'the vessel as a fine powder while actively stirring, and the mixture 1s heated to about 80 centigrade. With a current density of three hundred amperesfiper square meter the tension is 1.6 volts. ter a short time anthraquinone may be proved. If a somewhat greater current quantity then the theoretical one has assed the electrolyte, the anthraquinone need only be filtered, and the electrolyte maybe used for another opera: tion. 1

, Example I1."Omidation lg none, (hydrogu'inone.)-In ernian Patent N 0. 117,129 a process for producing quinone from anilin has been described; but it sgecially refers to the use of a diaphragm. e-

1ds of vanadium are of advantage in this procoxid, (Z. f. Anorg. Ohemie, 35, 156.) The ex dium oxids (V ,O is shown in Example I. A

more or less strong reducing or Thus" German Patent No.

r05 sides the advantage of operating without a cathode. In the hydrochloric acid heated to apparatus as in Example I. As electrolyte sulfuric acid of tWenty-per-cent. strength is used with an addition of two per cent. of vanadic acid, the process is best carried out at a temperature not exceeding centigrade. With a current density of four hundred am- -peres per s 1are meter the tensionis 3.6

volts. The ydroquinone is isolated in the usual manner.

Example 111 .Reduction of abenzene.

Into a vessel lined with lead and serving as cathode is introduced sulfuric acid of twentyper-cent. stren th, two per cent. of vanadium urioxid being issolved therein. Platinum, for instance, may be used as anode. electrolyte heated to centigrade isintroduced while stirring finely-pulverized azobenzene. The electrolysis is conducted with a current density of one to two hundred amperes, and on the completion of the process the benzidin sulfate is filtered,

Example1V.Reductionofazoaiybenzene. Into the cathode-compartment of an electrol tic cell divided by a diaphragm is introuced hydrochloric acid of fifteen-per-cent. strength, serving as electrolyte, with a quantity of vanadic acid dissolved thereinfor instance, one per cent. carbon being used as 50 centigrade azoxybenzene is'suspended and stirred by means of an agitator. The anodeto leave the small qluantity of benzi Into the com artment contains, for instance, a satu-. rated solution of common salt, carbon being likewise used as electrode. density of three to four hundred amperes per s uare meter the tension is about three volts. The completion of the electrolysis occurs with a small excess of current quantity requisite for reducing azoXy-benzene to hydrazo-benzene. When cold, the solution of the separated benzidin chlorid is filtered. The so bility of the benzidin chlorid having been greatly minimized by the hydrochloric acid of fifteen-per-cent. strength,.it is (preferable in chlorid dissolved, for the ectrolyte may be used for another operation.

The electrodes may be arranged in the usual manner. It is therefore preferable and in the nature of this process to choose when operatin without a diaphragm a large active electro e in proportion to that of the other pole. 7

Having now described my invention, what I claim is- The herein-described process for treating organic substances, which consists in subjecting the same to electrolysis in an acid-bath in the presence of vanadium compounds' In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

ERICH OPPERMANN.

With a current 

